Press TV - US President Donald Trump says that the United States is “locked and loaded” for a possible response to the recent Yemeni drone attacks on Saudi Arabia's oil facilities.

Trump took to Twitter on Monday, saying that Washington has a "reason to believe that we know" who is responsible for the attacks carried out against the kingdom’s key oil facilities in Abqaiq and Khurais on Saturday.

US Secretary of State Mike Pompeo put the blame for the operation on Iran, claiming, “Tehran is behind nearly 100 attacks on Saudi Arabia” and that “there is no evidence the attacks came from Yemen.”

Tehran, however, dismissed the allegation, saying Washington seems to be shifting from a failed campaign of “maximum pressure” to one of “maximum lying” and “deceit” against the Islamic Republic.

Iranian Foreign Minister Mohammad Javad Zarif said in a tweet that “US & its clients are stuck in Yemen because of illusion that weapon superiority will lead to military victory.”

Yemen said it used 10 drones for Saturday’s operation, which was one of their largest retaliatory attacks ever inside the kingdom.

The Yemeni army has said the raids were carried out on the back of an intelligence operation and in cooperation with “certain honorable and freedom-seeking individuals within Saudi Arabia.”

Yemeni fighters regularly target positions inside Saudi Arabia in retaliation for the Saudi-led offensive, which began in March 2015 in an attempt to reinstall the country's Riyadh-allied former regime and crush the Houthis.

The US-backed military aggression, coupled with a naval blockade, has killed tens of thousands of Yemenis, destroyed the country’s infrastructure and led to a massive humanitarian crisis.